The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrate processing systems for performing deposition and/or etching typically include a processing chamber, a gas distribution device such as a showerhead and a substrate support. A substrate such as a semiconductor wafer may be arranged on the substrate support. During processing, different gas mixtures may be introduced into the processing chamber and then evacuated. The process is repeated multiple times to deposit film, to etch the substrate or to perform other substrate treatment. In some substrate processing systems, radio frequency (RF) plasma may be used to activate chemical reactions.
Some substrate processing systems use a reaction zone between the substrate and the gas distribution device. The reaction zone may be isolated from a large processing chamber volume using a gas curtain. The large chamber volume helps to mitigate parasitic coupling to grounded processing chamber walls (due to the increased distance). However, the large chamber volume also has dead volumes that can accumulate particles, which may increase defects.